• (a.) Thin iron sheets coated with an alloy of lead and tin; -- so called because made up of three metals.
steel sheet with a coating of terne metal, an alloy of lead and tin applied by dipping the steel in molten metal. The alloy has a dull appearance ...
Sheet iron or steel coated with an alloy of lead and tin. 
Terne'plate` noun [ See Tern , adjective , and Plate .] Thin iron sheets coated with an alloy of lead and tin; -- so called because made up of three metals. 
Steel sheet coated with a lead-tin alloy. Traditional roofing material.